Why cocaine is stimulant?

Cocaine acts on the central nervous system as a dopamine reuptake inhibitor. The build up of dopamine results in coke's gleeful carelessness. It suppresses appetite and increases alertness by the continued activity of dopamine receptors. There is research connecting this with thrill seekers using adrenaline from the fight or flight response mechanism as a naturally internal chemical snort. That's why so many skydivers/bungie jumpers get literally addicted to fear-inducing activities.